In the chick embryo, the acellular portion(s) of the primary corneal stroma is composed of a series of layers or plies, each composed of numerous striated fibrils which are equally spaced from one another. Fibrils in alternate layers are arranged essentially orthogonal to one another with some of the layers in each eye being precisely rotated a few degrees in a clockwise direction. Our recent observation that the primary corneal stroma is composed of two genetically different collagens, type I and type II, both of which are synthesized by the corneal epithelium, has raised a number of questions as to how these molecules are themselves assembled, and how they may interact in the formation of the primary stroma. We propose to establish the role that collagen precursor chains play in the correct molecular assembly of the two collagen types that are found in the primary stroma, and spatially how these two collagens arrange in the stroma. We also will investigate whether posttranslational glycosylation of the two types of collagen might be involved in determining the precise fibril diameter found in the cornea. Then, as an initial step in determining the possible role(s) these different collagens play in corneal morphogenesis, we will establish the temporal sequence through which the corneal epithelium acquires the production of the two different collagens and see whether changes in the synthesis of these two molecules correlate with any of the major morphogenetic events which occur during corneal development, e.g., orthogonality, rotation, fibroblast invasion. We will analyze these collagens by biochemical methods and immunological procedures using conventional and monoclonal antibodies for the different collagen types.